Chewing gum composition



Patented June 29, 1937 PATENT OFFICE 2,085,490 CHEWING GUM COMPOSITIONKenneth G. Blaikie, Shawinigan Falls, Quebec, a, assignors to ShawiniganChemicals Limited, Montreal, Canada, a corporation of Canada No Drawing.-Application August 14, 1933. Serial No. 685,075

10 Claims.

This invention relates to a composition of matter suitable for use aschewing gum. The base of chewing gum now extensively sold is gum chicle.This material has certain disadvantages, particularly its high price andthe sticky nature of the material, rendering the gum made therefromdiflicult to remove from material on which it is deposited.

According to this invention, certain polyvinyl esters having suitableviscosity form an excellent complete or partial substitute for gumchicle as a base for chewing gum compositions. The polymers whenproperly made and purified are tasteless and insoluble in water orsaliva and are not as sticky as gum chicle, but possess the desirableproperties of gum chicle and do not harden on continued chewing. Thepolymers may be readily incorporated with fillers, plasticizers,softeners, sugar, flavoring matter, and with medicinal, antiseptic,prophylactic, deodorizing or other agents, etc., and may be formed intosticks, sheets or pellets, which at ordinary temperature and whensubstantially water-free are about as hard as ordinary unchewed chiolegum. When chewed, however, the polymers take up moisture and become softand ductile. In this state and when warm, the polymers may be pulled outto great length and the resulting thread rolled up and quickly kneadedinto a homogeneous mass.

Among the polyvinyl esters, polyvinyl acetate having viscosity betweenapproximately 1.5 and 6 centipoises and made according to the teachingof the examples hereinafter given is particularly suitable as a chewinggum base and,

to facilitate and simplify explanation, the following description willbe substantially confined to the use of polyvinyl acetates in theprepara tion of the compositions. A polymer with viscosity between 1.8and 4 centipoises is now believed to be the most satisfactory.

In order that there will not be any uncertainty as to the physicalconsistency of the polymers, it may be stated the viscosities hereinmentioned are determined as follows:

The polymer is dissolved in benzene and made up so that at 20 C. onelitre contains the simple molecular weight of polymer in grammes. Thisis filtered into the apparatus through cottonwool, precautions beingtaken to avoid loss of solvents. The time of outflow is then determinedby the Oswald viscosimeter, which has been standardized on a puresolvent (benzene), of which the absolute viscosity is known in centiwiseThe polyvinyl acetate may be prepared, in general, according to themethods disclosed in United States Patent No. 2,007,557, granted July 9,1935, and may be combined with between 10% and 50% of suitable fillers,such as infusorial earth, powdered talc or bntonite; with between 10%and or more of a suitable water insoluble plasticizer, such as diamyl,dibutyl, benzyl or glycol phthalate, glycol borate or a rezyl, and, ifdesired, with between 5% and 50% of water soluble softeners such aspolyhydric alcohols, particularly those of the aliphatic series, forexample glycerol or a suitable glycol, such as ethylene, butylene,diethylene or propylene glycol, or a mixture of any one or more of thesewith glycerol.

The amount of filler that can be used is less with polymers of higherviscosity than with polymers of lower viscosity and, conversely, theamount of plasticizer required'is greater with polymers of higherviscosity than with those of lower viscosity. The amount of softenerused will depend on viscosity of the polyvinyl acetate and the amount offiller and/or plasticizer in the composition andthe desired hardness ofthe composition at ordinary atmospheric temperature and at bodytemperature.

Polyvinyl acetates of the viscosities stated, even when at bodytemperature and mixed with a plasticizer, do not take up water andsoften as rapidly as is desirable in a chewing gum composition. For thisreason, it is desirable to incorporate a water soluble softener which,on initial chewing of the-composition, dissolves out rapidly and isreplaced in the composition by water to form an emulsion of the desiredcon sistency.

The requirements of suitable plasticizers are compatibility with thepolyvinyl ester; insolubility in water and saliva; substantialtastelessness; and absence of any toxic or undesirable physiologicalefiect. These requirements are met by the higher esters of phthalicacid, for instance, diamyl and dibutyl phthalate. 45 Neither of theseesters is completely tasteless of itself, but their solubility in salivais so decreased in presence of polyvinyl acetate that the resultingproduct is tasteless.

Obviously, the softening agent must be compatible with the polyvinylester and must not have any undesirable taste or physiological effect.

The following examples will illustrate various methods of practicing theinvention:-

Example I A mixture composed of 30 parts of toluene, '70 parts of vinylacetate containing not more than .05% of acetaldehyde, and 0.6 part ofcatalyst prepared from sodium perborate and acetic anhydride, asdescribed in Patent No. 2,007,557 is placed in a kettle, preferablyenamel lined, and fitted with a return flow condenser, and emcientagitator, a thermometer and a draw-oil line connected to the kettlethrough a seal. The contents of the kettle are heated until refluxingbegins. As polymerization proceeds, the temperature rises. When atemperature of 87 to 88 C. is attained, a mixture or vinyl acetate,toluene and catalyst in the same proportions as the initial charge isrun in at such rate that the temperature remains constant at 87 to 88 C.Eventually, the mixture of unchanged vinyl acetate, toluene andpolyvinyl acetate reaches the draw-oil! and overflows therethrough intoa container or into a still fitted up for steam distillation. Theprocess may be run continuously and the polyvinyl acetate, which isseparated in the still from toluene and uncharged vinyl acetate, isdried until its contains not more than 1% of water by weight. Theviscosity of the polymer is 2.5 centipoises. covered from the still maybe dried and it and the vinyl acetate can be used over again.

The dried polyvinyl acetate is crushed to substantially pulverulentcondition and 100 parts by weight are mixed with 25 parts of diamylphthalate, 35 parts infusorial earth, 18 parts glycerol and 2 partspropylene glycol, at a temperature of about 100 C. until a smooth pasteis obtained. Flavoring matter or a medicinal agent may be added asdesired. The chewing gum base obtained as above is firm and nonsticky atroom temperature and can be readily handled. It may be compounded withsugar and formed into sticks or pellets which are nonsticky and which donot harden during storage for considerable periods of time.

Example II A mixture of parts toluene, .parts vinyl acetate and 1 partof catalyst is polymerized at 90 C. as described in Example I. Thepolyvinyl product has a viscosity of 1.8 centipoises and can beincorporated with fillers, plasticizers and softeners to produce asatisfactory chewing gum base. In this case, less plasticizer isrequired as the polymer is softer than that produced according toExample I. 15 parts of plasticizer are sufficient to produce asatisfactory material.

By varying the proportion of toluene between 30% and 40%, a polymer ofany desired viscosity between 2.5 and 1.8 centipoises can be readilyobtained. By varying the proportion of toluene between 20% and 30%,polymers of viscosity between 2.5 and 3.3 centipoises can be obtained.If polymers of higher viscosities than 3.3 are desired, it is preferableto heat the mixture of vinyl acetate and toluene with the catalyst untilit thickens and then discharge the entire contents of the kettle intothe steam still. A mixture of parts vinyl acetate, 30 parts toluene and0.6 part catalyst when treated in this way yields a polymer having aviscosity of 3.5 centipoises, while the product of a mixture of 80 partsvinyl acetate and 20 parts toluene has a viscosity of 6.3 centipoises.

The polymers produced according to any of the above variations of themethod may be mixed The wet toluene recosity than for polymers of lower'viscosity. The

relative proportions of glycerol and glycol may vary considerably fromthe proportions given in Example I and the proportion of softener to thepolymer may be more or less than given in Example I according to theviscosity of the polymer, the amount of plasticizer and flller, and thecharacteristics desired in the finished product.

Furthermore, polyvinyl acetates of two or more difierent viscositiesmade according to the teaching of the foregoing examples may be blendedtogether to produce a chicle substitute, and in such case,- theviscosity of one polymer may be more than 6 centipoises and theviscosity of another may be less than 1.5 centipoises.

While the only polyvinyl ester so far dealt with is polyvinyl acetate,it will be understood the polymers of other aliphatic vinyl esters, suchas butyl acetate and propyl acetate, may be used instead .of vinylacetate as hereinbefore described, or may be blended with a vinylacetate polymer and the other ingredients of the composition.

Having thus described my invention, what I claim is;-

l. A chewing gum composition comprising as the essential ingredientpolyvinyl ester having an average viscosity between 1.5 and 6centipoises, characterized by absence of bitterness and prepared fromvinyl ester containing not more than substantially .05% of aldehyde.

2. A chewing gum composition comprising as an essential ingredientpolyvinyl acetate having an average viscosity between 1.5 and 6centipoises, characterized by absence of bitterness and prepared fromvinyl acetate containing not more than substantially .05% ofacetaldehyde.

3. A chewing gum composition comprising polyvinyl acetate having anaverage viscosity between 1.5 and 6 centipoises, characterized byabsence of bitterness and prepared from vinyl acetate containing notmore than substantially .05% of aldehyde, and a substantially waterinsoluble plasticizer'for the polymer.

4. A chewing gum composition comprising polyvinyl acetate having anaverage viscosity between 1.5 and 6 centipoises, characterized by abrsence of bitterness and prepared from vinyl acetate containing not morethan substantially .05% of aldehyde, and a readily water solublesoftening agent for the polymer.

5. A chewing gum composition comprising polyvinyl acetate having anaverage viscosity between 1.5 and 6 centipoises, characterized byabsence of bitterness and prepared from vinyl acetate containing notmore than substantially .05% of aldehyde, a substantially waterinsoluble plasticizer for the polymer, and a mineral filler.

6. A chewing gum composition comprising polyvinyl acetate having anaverage viscosity between 1.5 and 6 centipoises, characterized byabsence of bitterness and prepared from vinyl acetate containing notmore than substantially .05% of aldehyde, a readily water solublesoftening agent for the polymer and a mineral filler.

7. A chewing gum composition according to claim 5 in which the mineralfiller is included in the group consisting of kieselguhr, talc andbentonite.

8. A chewing gum base comprising as an essential ingredient polyvinylester having an average viscosity between 1.5 and 6 centipoises,characterized by absence of bitterness and prepared from vinyl estercontaining not more than substantially .05% of aldehyde.

9. A chewing gum base comprising as an essential ingredient polyvinylacetate having an average viscosity between 1.5 and 6 centipoises,characterized by absence of bitterness and pre- KENNETH G. BLAIKIE.

